Full-Stack Engineer (AI)

Company: Variabl
Experience: 0–4 years (Strong freshers welcome)
Employment: Full-time
Location: Koramangala, Bengaluru

About Variabl
Variabl is building an AI-first fintech platform for businesses and consumers.

Our platform brings together invoicing, payments, GST, accounting, cash flow, and everyday financial operations into one connected experience.

At the heart of Variabl is Maya, our AI agent.

Maya helps users draft invoices, record payments, issue credit notes, and understand their finances by interacting with real financial data and tools.

We're a small team where engineers take ownership of features from start to finish, from database architecture and AI integrations to the final user experience.

This isn't a role where you simply pick up tickets and write code.

You'll work directly with our founders, Chartered Accountants, and product team to understand real financial problems and build software that solves them.

What You'll Work On

1. Full-Stack Product Development

Build end-to-end features across frontend, backend, databases, and APIs.
Develop responsive, intuitive, and high-performance user interfaces.
Design scalable backend services, authentication systems, and background jobs.
Take features from idea to production and continuously improve them.

1. AI Agents & LLM Integration

Build and improve Maya, our AI-powered finance agent.
Integrate LLMs such as Claude, Gemini (Vertex AI), and OpenAI models.
Develop agent tools, function schemas, system prompts, and multi-step workflows.
Implement structured outputs, streaming responses, and AI-powered interfaces.
Improve AI reliability through validation, error handling, retries, and confirmation mechanisms.
Optimise AI performance for accuracy, latency, and cost.
Build MCP servers and APIs that enable other AI applications to interact with our platform.

1. Backend & API Development

Design and maintain RESTful APIs using Python and FastAPI.
Develop secure and reliable backend services.
Build integrations with external services and financial platforms.
Implement authentication, authorisation, data validation, and error handling.

1. Database & Financial Systems

Work with PostgreSQL to design schemas, queries, migrations, and transactions.
Build reliable systems for invoices, payments, accounting, and financial records.
Understand and implement financial workflows involving GST, TDS, reconciliation, and reporting.
Maintain data accuracy, consistency, and integrity across the platform.

1. Frontend & User Experience

Build modern web applications using React, Next.js, and TypeScript.
Create clean and intuitive interfaces using Tailwind CSS, shadcn/ui, and Radix.
Develop AI-native experiences such as interactive chat interfaces, streaming responses, and dynamic UI components.
Pay attention to design details including layout, typography, spacing, responsiveness, and interactions.

1. Third-Party Integrations

Integrate payment gateways, banking APIs, and Account Aggregator systems.
Work with KYC providers, GST platforms, and financial data services.
Develop reliable integrations between AI agents, internal services, and external APIs.

1. Deployment & Engineering

Deploy and maintain services on Google Cloud Platform (GCP).
Work with Docker, Git, testing frameworks, and deployment pipelines.
Monitor application performance, debug production issues, and improve system reliability.
Write clean, maintainable, and well-tested code.

What We're Looking For

Strong Full-Stack Fundamentals
0–4 years of experience building web applications.
Hands-on experience across frontend, backend, and databases.
Strong programming fundamentals and problem-solving skills.
Ability to independently develop and deploy a complete application.

Frontend Development
Strong knowledge of JavaScript/TypeScript and React.
Experience with Next.js, HTML, CSS, and Tailwind CSS.
Understanding of responsive design, state management, and API integrations.
Attention to UI design and user experience.

Backend Development
Strong Python programming skills.
Experience building REST APIs using FastAPI, Flask, or Django.
Understanding of HTTP protocols, API design, authentication, and authorisation.
Familiarity with Pydantic and SQLAlchemy is a plus.

Database Knowledge
Strong SQL fundamentals.
Experience working with PostgreSQL.
Understanding of database design, joins, indexes, migrations, and transactions.
Attention to data precision and integrity.

AI & LLM Engineering
Practical experience building applications using LLM APIs, with an understanding of:
Tool calling and function calling.
Prompt engineering and system instructions.
Multi-step AI agent workflows.
Agent frameworks such as Google ADK, LangGraph, or OpenAI Agents SDK.
Structured outputs and streaming.
Context management, sessions, and memory.
Model accuracy, token usage, latency, and cost optimisation.
Testing and evaluating AI-generated outputs.
Development Fundamentals
Git and GitHub.
Docker.
Debugging and testing.
Understanding of cloud deployments.
Ability to understand and work with existing codebases.

How We Work

Ownership: You take responsibility for what you build, from understanding the problem to shipping and improving the solution.

Speed: You enjoy building and shipping quickly while maintaining quality.

Attention to Detail: You notice the small things, whether it's a UI inconsistency, a rounding error, or an overlooked edge case.

Problem Solving: You think beyond the immediate requirement and try to understand the underlying problem.

Curiosity: You're excited to learn about finance, AI, and new technologies.

Product Thinking: You care about how people experience your work, not just whether the code runs.

Nice to Have
Experience with fintech, accounting, GST, invoicing, payments, or UPI.
Familiarity with Cashfree, banking APIs, Account Aggregators, or KYC integrations.
Experience with React Native, Flutter, or mobile applications.
Design experience using Figma.
Familiarity with Cloud Build, CI/CD, background workers, or PostHog.
Experience building AI agents used in production.
Knowledge of MCP servers, AI agent skills, and prompt caching.
Experience with LLM evaluations, tracing, and observability.
Familiarity with RAG, embeddings, and document extraction.
Experience with Node.js, Express, or Clerk.
Open-source contributions, hackathon projects, or independently built products.

*Freshers Are Welcome!
*
We care more about what you've built than where you've studied or how many years of experience you have.

If you're a fresher, we'd love to see:
One or two complete full-stack projects you've built independently.
A live application or GitHub repository demonstrating your work.
Experience building a frontend, backend, database, authentication, and deployment.
At least one AI-powered application using LLMs, tool calling, or agent workflows.
Thoughtful UI design and attention to the overall user experience.
Projects that go beyond tutorials and solve real problems.
Experience building a finance, payments, or money management application is a bonus.

Why Join Variabl?
Build real products: Work on software used for real financial operations.
Own your work: Take responsibility for meaningful features from day one.
Work with AI: Build production-grade AI agents that interact with real financial data.
Learn finance: Work closely with Chartered Accountants and finance founders.
Grow quickly: Join a small, fast-moving team where your contributions directly shape the product.
Solve meaningful problems: Help make finance simpler and more accessible for businesses and individuals.

How to Apply

Share your:

Resume
GitHub profile or portfolio
A project you've built that you're particularly proud of
A short explanation of what interests you about AI, finance, or fintech

We'd especially love to hear about the most interesting application you've built using an LLM.

Our Hiring Process
Short introductory conversation
Practical take-home assignment or live build exercise
Technical discussion about your work
Final conversation with the founders

Interested in building the future of finance with AI?

We'd love to hear from you.